Heating of fluids



Aug. 4, 1936. 1D. SEGUY 2,049,473

HEATING 0F FLUIDS Filed March 17, 1953 2 Sheets-Sheet l Allg'.v 4, J, D SEGUY i 2,049,473

HEATING OF FLUIDS Filed March 17, 1953 2 Sheets-Sheet 2 Patented Aug. 4, 1936 I 2,049,473

UNITED; srarlazsv PATENT ori-ics 2,049,473 HEATING F FLUIDS Jean Delattre Seguy, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application March 1'1, 1933, Serial No. 661,273 8 Claims. (Cl. 122-356) This invention relates to an improved form of furnace structure embodying the features and adfurnace and method of heating, particularly vantages of the present invention. Figure 1 is a adapted to the heating of hydrocarbon oils to consectional elevation of. the furnace and Figure 2 is version temperatures, of the type wherein the another sectional elevation of the same struciluid conduit is subjected to substantially uniform ture taken at right angles to Figure 1 along a 5 heating on opposite sides substantially only by plane indicated by the line 2?-2 in Figure 1.

direct radiation from sources of heat, the im- Referring to the drawings, the main furnace provements of the present invention comprising structure comprises side walls I and I', end walls the controlled recirculation of combustion gases 2 and 2', a roof 3 and a oor d. A single ver- 10 over the fluid conduit in such a manner as to tical row 5 of horizontally disposed tubes 6 con- 10 effect a positive control over the fluid heat input nected, in the case illustrated, in series, by means to the tubes from the combustion gases and to of suitable return bends or headers 'l located modify the radiant heating effect from the names outside the heating zone, comprisesthe fluid conand hot refractory surfaces of the furnace. duit through which the hydrocarbon oil or other In the preferred embodiment of the invention material to be heated is PaSSBd- The tube bank 15 combustion products withdrawn from the furnace or uid conduit 5 is centrally located between the are passed, by means of a suitable recirculating side walls I and l', similar combustion zones 8 fau or blower, over theiiuid conduit, preferably and 8 being provided on Opposite sides of the in a. direction concurrent to the general direction uid conduit.

of the flame in the combustion zones, said recir- Any'suitable combustible fuel such as oil, gas 20 culating combustion gases forming a channel or or'pulverized solid fuel is supplied by means of i enveloping layer of gases on both sides of the uid suitable burners 9 through firing ports 9 located, conduit. In the case of a furnace enclosing a in thecase illustrated, in the roof of the furnace fluid conduit comprising a vertical bank of horit0 Combustion 201165 8 and 3. Preferably, aS i11- zontally disposed tubes with combustion zones dicated by burners 8 and firing ports 9', the 25 located on opposite sides of the fluid conduit, combustibles are directed in ageneral downward combustibles supplied thereto in a downward didirection and at a slight angle toward the side rection and flue gases removed from the lower walls I and I. This serves to assist combustion portion of the furnace, constituting-what may and uniform distribution of the combustibles,

be termed a top-fired down-draft furnace, coincausing the refractory walls I and I to be heated 30 bustion 'products are removed from the combusto a radiant condition and assists in preventing tion zones and are forced from a point above the ame impingement of the tubes 6. Direct rafluid conduit over the tubes in a downward direcdiation from the flames in combustion zones 8 tion to an exit beneath the uid conduit, thus and 8' on opposite sides of the fluid conduit as setting up a cycle of enveloping gases around the well as radiation from the highly heated refrac-l 35 tubes. Since the enveloping combustion gases tory walls of the furnace imparts heat to oppo- A are substantially the only fluid heating medium site sides of each of the tubes 6 of the fluid concoming into direct contact with the tubes, their duit whereby a high average rate of, heating controlled recirculation serves as a means of conaround the entire circumference of each tube is 40 trolling the uid component of the total heat secured. The combustion gases leave combus- 40 input to the tubes, thereby constituting an addition zones 8 and 8 through the openings l0 and tional and positive means of regulating, within I0' respectively in the floor 4 of the furnace and suitable limits, the rate of total heat input to the pass through the space provided between the floor tubes. Obviously the enveloping layer of circut and the sub-floor II to flue I2 from which a.

lating combustion'gases around the fluid conduit regulated portion of the combustion gases cooled 45 serves to modify the radiant heat component supand diluted by recirculated gases, as will be later plied to opposite sides of. the tubes by direct'ramore fully described, pass through regulating diation from the flames and from the hot refracdamper I3 to a stack, not shown.y tory surfaces of the combustion zone. Also by In accordance with the provisions of the pres- 50 surrounding the tubes with an enveloping layer ent invention, a portion of the combustion gases of combustion gases they are protected from from combustion zones and 8' are withdrawn direct impingement of the names and any consefrom flue I2 through duct It to a suitable flue quent localized overheating. gas recirculating fan I5, driven by van electric r The accompanying diagrammatic drawings motor or any other suitable motivating means,

5" (Figures 1 and 2) illustrate one specific form of not shown in the drawings, by means of which 55 the combustion I 6 controlled by damper I1 to a distributing header I8 wherefrom they are directed through port I9 in the roof of the furnace downward along opposite sides of the tubes 6 of the fluid conduit,

forming a streamor channel of-combustion gasesenveloping the tubes and flowing downward through the furnace in a direction concurrent to the general direction of firing andl the flow of hot combustion gases passing through ports I and I0'. The recirculated combustion gases having passed over the tube bank flow through port 20 in oor 4 of the furnace to flue I2. Refractory blocks 2I placed above port I9 and above the opening in sub-floor II to flue I2 and spaced at the desired intervals serve as a means of evenly distributing the recirculated combustion gases along the entirel length of the tubes 6 in the heating zone. Although not illustrated in the drawings, duct I6 and the distributing header I8 as well as the recirculating fan I5 preferably are well insulated in order to avoid excessive cooling of the recirculated combustion gases. By control of damper II and/or the speed of fan I5 the velocity of the recirculated gases and the volume of such gases flowing over tube bank 5 in a given time is controlled, thereby positively and effectively controlling the fluid heat input to the tubes and modifying the radiant heat With the flue gas recirculating features of the.

present invention an additional and positive means of controlling the heating conditions is afforded, the recirculated gases serving to modify the intense heat imparted to the tubes by radiation from the flame and hot refractory walls of the furnace.

.It will be understood that the features of the present tially only .by radiation.

I claim as my invention: 1.- In a process for the heating of fluids wherein the fluid is passed through a conduit, within a 2,049,473 gases are directed through duct' combustion and recirculating said stream through the furnace in a layer enveloping the uid conduit to serve as a gaseous protecting medium on both sides of the conduit and modify the effect of such radiation.

3. In a process for the heating of fluids wherein the uid is passed in provement which comprises continuously withdrawing a stream of combustion gases from the furnace and recirculating said stream through the furnace over the :duid conduit in such a manner as to modify the effect of such radiant heating on both sides of the conduit.

4. In a process for the heating of fluids wherein the fluid is passed in a. continuous stream through a fluid conduit comprising tubular elements located within a furnace, opposite sides of each element being heated by direct radiation from the combustion of which comprises continufrom the furnace and recirculating said stream over the fluid conduit in such a manner as to modify the effect of such heating by radiation on both sides of the conduit.

5. In a furnace for the heating of uids having a uid conduit comprising a plurality of tubular elements located in a common vertical plane within a furnace sin'ucture, combustion zones located on opposite sides of the iiuid conduit, means for supplyingcombustible fuel thereto and effecting its combustion in such a manner that opposite sides of each tubular element of the fluid `conduit are heated by direct radiation from flames resulting from such combustion and means for continuously removing combustion gases from the combustion zones, the improved method of operation which comprises continuously withdrawing from the furnace a stream of the combustion gases and recirculating said stream through the furnace and over the fluid conduit in an enveloping layer which serves to protect both sides of the fluid conduit from overheating by modifying the effects of such radiant heating.

6. In a furnace for the heating of fluids having a fluid conduit comprising a plurality of tubular elements located in a common vertical plane within a furnace structure, combustion zones located on opposite sides of the fluid conduit, means for supplying combustible fuel thereto and effecting its combustion in such a manner that opposite sides of each tubular element of the fluid conduit are equally heated by direct radiation from llames the effects of such radiant 7. A heating apparatus comprising a furnace having a pair of heat radiant walls, a. fluid heating 5 having a pair of heat radiant walls, a plurality of horizontal heating tubes disposed in avertical plane between 'and spaced from said walls, means for mpinging flame downwardly and angularly against each of said walls on the side thereof facing the tubes, means for withdrawing combustion gases from the furnace, and means for recirculating a portion of the withdrawn gases downwardly through the furnace in an enveloping layer over the tubes. v JEAN DELATTRE SEGUY. 

